1.21. Software Hardware Environment Liveware (SHEL) model by Edwards

Another model of understanding the interrelations of socio-technical system components is Edwards’ SHEL model (Edwards, 1972). The author introduced the Software, Hardware, Environment and Liveware (SHEL) model in the context of safety-critical systems (see figure 1). Thereby, the components stand for:

S - Software: Non-material part of systems which includes practices, procedures, regulations etc.

H - Hardware: Technical systems and equipment, also tools and manuals etc.

E - Environment: The Environment includes all external influences and factors such as policies, cultural restrictions, etc.

L - Livewire: The Human as component. This component includes operators, managers and clients being involved in the productive process.

The important aspect is the interaction among the three components in order to achieve a certain objective. Consequently, the heart of the model are the communication and relational aspects of the model.

The SHEL Model expresses the interrelationships and interdependencies of different systemic components on the one hand and the human component on the other hand under the influence of environmental conditions. Edwards’ observations are that socio-technical systems are always shaped by the three components S H L embedded in an E. Any change of a component impacts the others. When introducing e.g. a certain technology into a working environment, this has, consequently, an implication to the people working in the environment and to the processes in this environment.





Figure 1: The SHEL model by Edwards

The combination of hardware, software and human resources do not exist in vacuum. They always operate in a context of economic, political, historical or socio-cultural factors. However, environmental factors are in the minority of cases subject of change or even changeable.

Kawano (2002) extended the SHEL model of Edwards into the m-SHEL model by adding an ‘m’ for management (control of the system).

The SHEL model serves as a basic understanding for eParticipation as a multi-disciplinary and socio-technical system context.





References:

Edwards, E. (1972). Man and machine: Systems for safety. In Proc. of British Airline Pilots Associations Technical Symposium, (pp. 21-36). British Airline Pilots Associations, London

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